Short-eared elephant ( Macroscelides proboscideus )
|Scientific name of the order|
|Butler , 1956|
|Scientific name of the family|
|Bonaparte , 1838|
The elephant jerks (Macroscelididae) are a family of mammals that also form the order of the Macroscelidea of the same name in German . They inhabit the central, eastern and southern and with one representative also the northern area of Africa . The group currently comprises 20 species in six genera. The animals are small ground dwellers, which are characterized by a large head with a trunk-like elongated nose as well as a long tail and thin limbs. The hind legs are significantly longer than the front legs, and the feet and lower limbs are also elongated. As a result, the elephants have extremely good running properties, so that they can move quickly running or jumping. The main food consists mainly of insects and other invertebrates , with a small amount of plants added. Males and females form monogamous couples, the bond of which lasts throughout life. The individual territories or territories of the animals partially or completely overlap in the pairs, but outside the mating season, the respective partners live solitary. The breeding of elephants is characterized by a comparatively long gestation period and a low number of offspring per litter.
The elephant was first known to western science towards the end of the 17th century through observations in southern Africa. The naming of the first species followed over a hundred years later. Because of their external appearance, the animals were compared with the shrews for a long time and placed in a family relationship with the insectivores . This opinion was still valid well into the 20th century, even when the elephants were placed in their own order in the mid-1950s. In the 1970s to 1990s, some scientists favored a closer look at rodents . Only genetic studies at the turn of the 21st century revealed a closer relationship between the elephant and other originally African animal groups such as the tenreks , the golden mole rat and the aardvark . The tribal history of the elephant as a family goes back to the Eocene and took place entirely on the African continent. Most of the fossil finds are made up of tooth and dentition remains. New discoveries and more recent findings from the beginning of the 21st century suggest that the origin of the group lay in today's Holarctic and dated to the Paleocene .
Elbow jumpers are somewhat similar to shrews , but are usually much larger. They reach a total length of 17 to 58 cm, the tail takes 8 to 26 cm. This makes the tail length about 80 to 120% of the length of the rest of the body. The relative tail length is often an important differentiating criterion between the individual species. The weight of the smaller shapes ranges from 22 to 280 g, while the slightly larger proboscis can weigh between 320 and 750 g. A sexual dimorphism is hardly developed with regard to body size. The color of the fur on the upper side varies depending on the habitat from yellow-gray to reddish brown to dark brown, the underside is lighter - usually whitish or light gray. The trunk has a distinct to inconspicuous streaky pattern of spots on the back, and stripes can occasionally appear on the trunk . The fur covering consists of the top hair and the undercoat . The top hairs of the back are 11 to 18 mm long and are partly thickened in the middle. Their diameter is 40 to 70 μm and the cross-section is mostly round. The hair scales form a wavy pattern at the base and a ring-shaped pattern at the top. In general, elephant dogs have a coarser and less dense fur than the other elephants.
The animals have large, round eyes, which in some species are framed by a conspicuous ring. The nose is characteristically elongated like a trunk and very mobile, the ears are relatively large. The long, almost hairless and thus rat-like tail is also striking. Another characteristic is the long and very slender legs, with the rear legs exceeding the front legs in length. The big toes (hallux) and the thumb (pollex) are either greatly reduced in size or completely absent. Depending on the species, scent glands can be formed on the soles of the feet, the chest, the anus and the tail, which serve for intra-species communication. In the case of the elephant shrews and the representatives of the genus Macroscelides , the females have three pairs of teats on the belly side of the proboscis dog and the trunk rat.
Skull and dentition features
The most important features that justify the delimitation of the elephant as a separate order ( autapomorphies ) can be found, as with most mammalian groups, in the structure of the bony skull. The skull essentially corresponds to the typical mammalian skull. It is relatively large and has a triangular shape when viewed from above with a long rostrum and a large and wide brain capsule. The zygomatic arches bulge out to the side and are completely closed. The orbit is very large and not closed at the rear by a completely closed bone brace ( postorbital brace ). The upper jaw has no part on the edge of the eye socket. In contrast, the palatine bone has large wings that form the front, lower edge of the eye socket. The nasal bone is generally long. In the view from below, the sometimes very complex perforation of the palatine bone, which occurs in all representatives of the elephant with the exception of the proboscis dog, and the inflated bony ear capsule ( bulla tympanica ) are particularly noticeable. This bloating is most advanced in Macroscelides , so that areas of the wart part , the scaly part , the parietal bone and the occiput are involved in the structure of the tympanic bladder. In Macroscelides, the volume of the two tympanic membranes taken together exceeds the brain volume; in Elephantulus and the other members of the elephant , both auditory structures are significantly smaller. However, they support the perception of low-frequency sounds in open landscapes. The lower jaw is long and slender, the articular branch protrudes very high so that the temporomandibular joint lies far above the occlusal plane. The crown process (coronoid process) is short and hardly rises above the articular process (condylar process). At the rear end of the lower jaw there is a pointed, hook-shaped angular process (angular process). A mostly double mental foramen is formed on the horizontal bone , which lies below the premolars .
The Rüsselspringer's tooth formula is: There are a total of 34 to 42 teeth. The upper incisors are missing in the proboscis dogs, the lower are two-pointed. In the case of the other elephants, they often have a nail-like shape at the top and bottom and are designed in different sizes depending on the species. In relation to the upper row of teeth, the elephant shrews have variable teeth; in the proboscis, the front incisor is significantly larger than the two rear teeth. Macroscelides and Galegeeska each have upper incisors of the same size, while the middle one is smaller in Petrosaltator . The upper canine is only reminiscent of a fang in the proboscis , otherwise it is small and variable like the lower one. The first two premolars are usually small, while the second is elongated in length and has one or two humps. The two back molars are broad in shape, the last one is strongly molarized and thus resembles the molars . All posterior molars have moderately high crowns ( subhypsodontic ) and a missing cingulum (a bulge or ridge at the base of the tooth). They are large, square in outline and have four pointed, sharp cusps on the chewing surface ( sectorial or secodontal tooth design). The arrangement of the protuberances and located between them leave a ripple dilambdodont extending cutting edge of the tooth enamel caused (in the form of the Latin letter W or two of aligned Greek lS ) whereby the teeth on a nod of hoofed animals. The last molar teeth are always missing in the upper jaw, in the lower jaw they occur occasionally in some species of elephant shrews and are then only very small. The elephants, like most mammals, have a change of teeth in which first a deciduous dentition and later a permanent second dentition are formed.
The spinal column consists of 7 neck - 13 Breast -, 7 to 8 lumbar -, 3 sacrum - and 20 to 28 caudal vertebrae . Compared to the other elephants, the elephants have on average more lumbar and caudal vertebrae, and they also have chevron bones on their tails . In all members of the family, the posterior lumbar vertebrae are characterized by long spinous and transverse processes to which the strong pelvic muscles are attached, which is related to the sometimes jumping locomotion. The forearm bones are fused together in most species, only in the elephant dog they are very close to each other. In these, unlike most mammals, the outermost finger ray has only two limbs. A special feature in the structure of the extremities are the long hind legs. In particular, the calf and shin bones are greatly elongated compared to the thigh bones , as are the metatarsals , which is a typical characteristic of fast-running animals. The lower leg section can exceed the upper section by 25 to 43% in length, and in some species the metatarsus is the same length as the thigh bone. A prominent third roll hillock (trochanter tertius) appears on the shaft of the latter. Two thirds of the two lower leg bones are fused together in the distal area.
Soft tissue anatomy of the nose
The trunk-like elongated nose of the elephants is highly flexible and constantly in motion, but in contrast to the similar formations as in the case of elephants and tapirs, not suitable for manipulating objects. Similar to the animals with a real trunk , the nose of the elephant has no bony substructure, which enables the high mobility. In the elephant dog, around 30 cartilaginous rings form the elongated nose, but this is based on examinations of embryos . In adult representatives of the elephant shrews, such cartilaginous ring structures are only present at the base of the nose. In the remaining part of the nose there is independent cartilage tissue as a nasal septum , which is partially perforated, and in the upper, lower and lateral areas. In addition, there are two main muscle strands: one that runs longitudinally to the side and one that runs transversely above. Both serve not only to move the nose, but are also able to change the size of the nostrils depending on the circumstances. An abdominal muscle that actively lowers the nose is missing. The nose is also covered with partly hairy skin. In these are sebum and less often sweat glands embedded. Overall, the nasal region of elephants does not appear to be highly specialized, as the animals have little control over the tip of the nose. As a result, the nose has less of a tactile function, but primarily serves as an olfactory organ, which, due to its extraordinary mobility, is related to the search for food in leaf waste or between stones on the ground.
The entire digestive tract of the small elephant shrews such as the elephant shrews and the species of Macroscelides is 51 to 60 cm long, in the proboscis it reaches 139 cm. The proportion of individual organs varies between the genera, the large intestine takes up between 16 and 20% in elephant shrews , 21% in macroscelides and only 9% in the proboscis. Possibly these variations are related to the ability to store water in arid habitats . In some elephant shrews, a change in the length of the digestive tract over the year at constant body weight has also been demonstrated, with noticeable reductions outside of the reproductive phase. The large appendix , which plays a major role in the digestion of vegetable food, is also striking . The kidneys have a single-lobed structure with a clearly separated cortical region, a medullary tube and an elongated papilla that extends towards the pelvis. The females have a two-horned uterus (uterus bicornis), which is less pronounced in the proboscis than in the other elephants. There is no cervix or a real vagina . The back of the body of the uterus functionally replaces the vagina. The testicles of the males are not located in an outer scrotum , they remain in the area of the kidneys and do not migrate downwards, as in many other mammals (primary testicle ). In the case of smaller species, their size is around 10 × 4 mm and weighs 0.08 g. In terms of body length, the penis is also relatively far forward, depending on the species between 20 and 40% in front of the anus , which in Macroscelides means a distance of about 4 cm. With 50 to 75% of the body length, the penis is extremely long when erect . The brain weighs 1270 to 1330 mg in the smaller elephant shrews and between 5400 and 7230 mg in the larger proboscis. Compared to animals with a similar way of life and diet, the trunk of the elephant has a larger brain on average.
distribution and habitat
The elephants are an endemic group of mammals found in Africa . The main distribution area is in the central, eastern and southern parts of the continent and extends from southern Sudan ( South Sudan ) and the Democratic Republic of the Congo to South Africa . Only one species, the North African elephant shrew ( Petrosaltator rozeti ), is native to the north and northwest from Morocco to Libya and is separated from the southern representatives by the Sahara . What is striking about the overall distribution of elephants is their complete absence in western Africa, as the Congo Basin with its large rivers Congo and Ubangi represent the northern and western borders of the southern occurrence. It is not clear why the elephants are absent from West Africa. It is possible that the large rivers and rivers represent barriers to expansion, as the animals' way of life does not favor floodplains or near-surface groundwater. In eastern and southern Africa, rivers such as the Tana , the Zambezi and the Orange limit the occurrence of some species.
The elephants inhabit a variety of habitats and landscapes, the following basic types can be distinguished:
- dry rocky landscapes and sometimes savannah areas interspersed with stone blocks or Kopjes or mountainous regions up to 2700 m above sea level; these include the Eastern ( Elephantulus myurus ) and the western rock elephant shrew ( Elephantulus rupestris ), the Cape Elephant Shrew ( Elephantulus edwardii ), the Karoo Cliff elephant shrew ( Elephantulus pilicaudus ), the North African Elephant Shrew and possibly also the Somali Elephant Shrew ( Galegeeska revoili ).
- dry scree fields, especially areas of the Karoo and Namib with only sparse vegetation; this includes all representatives of the genus Macroscelides .
- dry forest savannah and bushland with open vegetation on sandy soils with low grass and interspersed with scrub; these include the dryland elephant shrew ( Elephantulus intufi ) and the red-brown elephant shrew ( Elephantulus rufescens ).
- Mesian forest savannah and bushland with partly open, partly closed forests and thickets on different soils; these include the short-nosed elephant shrew ( Elephantulus brachyrhynchus ), the dark elephant shrew ( Elephantulus fuscus ), the dark-footed elephant shrew ( Elephantulus fuscipes ) and some subspecies of the proboscis ( Petrodromus tetradactylus ).
- Forests with a closed canopy and a rich layer of leaves on different soils; this includes a subspecies of the proboscis and all representatives of the proboscis dog ( Rhynchocyon ).
The diverse landscapes mean that different species occur together in some regions, but they then use a different habitat . Clinical adaptations to the environment in terms of coat color have also been demonstrated for individual representatives with a larger distribution area.
Way of life
The elephants live on the ground and are polycyclically active, mostly occurring during the day or at dusk. The animals usually rest during the greatest heat of the day. Some species such as the short-eared elephant ( Macroscelides proboscideus ) are also more active at night. The animals can move very quickly and reach speeds of up to 29 km / h. Two types of locomotion are known, a four-foot fast running ( cursorial ) and a jumping ( saltatory ). When running, the tail is kept horizontal and only placed on the ground when resting. The animals are adapted to the high running speeds due to their greatly elongated hind legs, especially due to the metatarsals which are almost the same length as the thigh bone. In saltatory running, the hind legs move synchronously with each other, while the front legs alternate, which is why this movement is also referred to as "half-jumping". Especially with the smaller elephant shrews such as the various representatives of the elephant shrews ( Elephantulus ) and the genus Macroscelides , it often happens that one of the hind legs does not appear, but rather remains hanging in the air at arrhythmic intervals. Possibly the animals correct the step frequency by the exuberant performance and take power from the run. This may be due to anatomical reasons, as the smaller elephants have a shorter torso than the larger elephants . Without these necessary corrections, the high level of power generated by the extraordinarily strong rear legs could lead to more frequent falls. The high jumps occasionally made when fleeing are similar to those of ungulates , such as springboks . The toe gait used when running , which seems atypical for numerous small mammals , is more reminiscent of ungulates, as is the slim physique, which is particularly noticeable in the proboscis and proboscis dogs. A frequently expressed assumption that the animals, like the kangaroos, would only move with wide leaps on their hind legs, is wrong, as is the opinion that they stand up on their hind legs. The representatives of Macroscelides and the elephant shrews who inhabit rocky or dry landscapes, mostly ground niches, rock crevices, termite mounds or even abandoned rodent burrows, look for hiding places . Since they are not very good at digging themselves, they rarely build their own earthworks. The trunk rat ( Petrodromus tetradactylus ) and the elephant shrews of the more overgrown regions, on the other hand, retreat into dense undergrowth. Proboscis dogs are known to build nests out of plant material.
Most species are territorial and have their own territories . Their size varies from less than 1 hectare to 100 hectares, depending on the inhabited region and the prevailing climatic conditions as well as the density of the local population . Some species of the elephant shrews and the genus Macroscelides as well as the proboscis are paths that connect the various activity points and shelters within a territory. These sometimes run straight through rocky landscapes or through dense vegetation areas. In some densely overgrown areas the paths only consist of individual cleared areas. The path system is used for fast locomotion and is created and cared for by the animals themselves, freeing the paths of stones, twigs or leaves with swinging arm movements. In contrast, the creation of paths has not yet been observed in the proboscis. Markings of the territories are made with the help of scented marks of secretion from glands , which, depending on the species, are located on the feet, chest, rump or tail. In addition to individual sounds, a drum-like noise is known as a means of communication. This foot drumming is generated with quick blows of the hind feet on the ground. This form of communication , known as podophony , consists of a fixed sequence of regular and irregular beats that only lasts for a short time, but is repeated after a certain time. The individual drum series vary according to the species and can thus be used as a taxonomic characteristic. A similar behavior has also been proven in some rabbits and rodents . The function of the foot drumming with the trunk jumpers is not entirely clear. The form of communication often occurs in stressful situations associated with territorial battles and mating rituals, but it can also occur in the presence of predators. Here it is possibly to be interpreted as a warning signal for conspecifics or as an indication to the predator that it has been noticed.
In general, the elephants live in monogamous pair bonds, which usually last their entire life. The territories of the tied animals partially or completely overlap. The pair bonds are not very deep, however, and joint activities rarely go beyond reproduction. However, the individual territories are defended against intruders, which is done by the partner of the same sex. One possible cause of pairing among elephants may be the greater intolerance of females to one another, as was observed in the eastern cliff elephant shrew. The higher aversion among females results from greater competition for food resources in the sometimes barren landscapes, while at the same time the mating partner is rather rare for the males. For the males, the likely benefits of a monogamous relationship are assured reproduction and the low cost of defending the female and / or common territory. This also reduces the risk that invading foreign males will mate with their partner. On the other hand, migrating males looking for receptive females would be more involved in the territorial defense of sedentary males. In addition, they are more likely to be preyed on by predators when roaming unknown terrain. Under certain circumstances, however, it can happen that a bound male moves to a neighboring territory whose owner is unbound or has lost her partner. This also results in a certain promiscuity in the male animals. According to studies, however, this often suffers a severe weight loss when maintaining two territories with one female each, which suggests that this way of life is expensive. Accordingly, the male mostly withdraws to his own territory when an unbound male appears. The behavior suggests, however, that the males of the elephants, in addition to reproducing within the pair, occasionally seek a transfer of their genes outside of these bonds, which in some species can also be recognized by the fact that male animals sometimes have significantly larger territories than females tend to cross borders more often.
Diet and thermoregulation
The main diet of elephants consists to a large extent of invertebrates . The elephants feed on a wide range of invertebrates, ranging from arthropods such as insects , spiders and millipedes to annelid worms . When foraging for food, they are increasingly opportunistic and only rarely selectively. For all other elephants an insect or omnivorous diet dominates with a preference for ants , termites and beetles . Depending on the season, they enrich their diet with plant-based food such as seeds , fruits and green parts of plants. In individual cases, nectar also plays a role, as a result of which some species also function as important disseminators of pollen . For morphological reasons elephants are not able to eat larger prey like smaller vertebrates . The excellent sense of smell is used to search for food , with the animals probing with their nose to search for leaf waste and other hiding places. The tongue is very long and can be stretched out several millimeters in front of the tip of the nose. With it the food is transported into the lower mouth, the molars with the sharp tips then chop up the prey. Unlike other mammals that feed on insects, elephants have a functional appendix that is responsible for digesting the plant-based parts of their food.
Especially the types of dry to desert-like landscapes with their hot days and cool nights show a certain heterothermia with a fluctuating body temperature during the day. To compensate for this, the animals stay in shady places or in cooler crevices during the hot phase. In the morning hours, however, extensive sunbathing can be observed. In addition, the kidneys in species in desert areas are able to accumulate urine to a high degree and thus reduce water loss. At very low night temperatures or in connection with poor food conditions, some representatives of the elephant shrews, especially the species of the genus Macroscelides and some representatives of the elephant shrews , fall into a torpor that lasts for several hours and in which the body temperature is only a few degrees above the Outside temperature drops. This behavior does not occur in the species that live in regions with more balanced climatic conditions, such as the proboscis or the proboscis dog.
Depending on the habitat and its climatic conditions, mating can take place all year round ( tropical areas) or less often depending on the season (regions of higher latitudes and mountainous areas). The sexual act usually only lasts a few seconds, the male performs this in an almost upright position. The relatively far forward position of the penis is seen as the cause of both . Some species of elephant shrews and the short-eared elephant shrews show in the germ cell development or -entlassung as a special one Polyovulation in which the Follikelsprung Although several mature eggs the ovaries are left and fertilized, however, these usually only two in the uterus embed . The animals always ovulate again after the young animals are littered (postpartum oestrus ). The cause of this polyovulation is still unknown. The gestation period lasts around six to ten weeks, which is relatively long for such small animals. As a rule, females have between three and six litters a year, depending on external conditions.
Usually one or two young animals are born, rarely a litter contains up to four newborns. The offspring of the proboscis puppies is born as a nestling and has little fur and closed eyes. In the case of the other elephants, the young are fleeing nests and can run within a few hours. The boys live in their own shelters, separate from their parents. The mother animal visits the young only briefly during the day to suckle them, which is known as the “mother's absenteeism system”. EG Franz Sauer coined the term in 1973 on populations of the short-eared elephant in the Namib , but the form of rearing has also been demonstrated in other well-studied elephants. One reason for this behavior could be that it keeps the offspring odorless, which provides better protection against predators. The sire, on the other hand, does not take part directly in rearing, but it can be involved indirectly by driving away or warning of predators. The suckling period lasts only two to three weeks, after which the young become increasingly independent and establish their own territories. Life expectancy in the wild is one to four years, depending on the size of the animals. The longest known age of an elephant shrew in human care was around nine years for a dryland elephant shrew and around eleven years for a golden elephant dog.
Internal systematics of Afrotheria according to Kuntner et al. 2011
The elephants are currently the only family in the order of the Macroscelidea, which is therefore monotypical . The Macroscelidea in turn represent a part of the parentage of Afrotheria , one of the four main lines within the higher mammals . The Afrotheria themselves are a molecular-genetic group, predominantly native to Africa or whose origin lies on the continent. Within the Afrotheria two larger kinship communities can be distinguished, the Paenungulata and the Afroinsectiphilia . The Paenungulata have long been known for their anatomical similarities and include today's elephants , hyrax and manatees . In addition to the elephants, the Afroinsectiphilia also includes the tenreks , otter shrews and golden mole , the last three mentioned together form the order of the Afrosoricida . As a rule, the aardvark , which is the only member of the order Tubulidentata, is also considered part of Afroinsectiphilia. The current data support a sister group relationship between the elephants and the aardvark as well as the Afrosoricida, the latter grouping is also sometimes referred to as Afroinsectivora. According to the molecular genetic studies, the Afrotheria have their origin in the Upper Cretaceous 90.4 to 80.9 million years ago. The split between the two main groups occurred about 15 million years later. The elephants first appeared in the course of the Lower Eocene between 49.1 and 47.5 million years ago, which agrees relatively well with the fossil record.
Internal systematics of the Macroscelididae according to Tabuce 2018
The positions of Palaeothentoides , Miosengi and Pronasilio were added after Holroyd 2010.
Within the order of the elephants (Macroscelidea) a recent family (Macroscelididae) with two subfamilies and currently 20 existing species is differentiated. The most species-rich group are the Macroscelidinae , which includes the species of the genera Elephantulus (elephant shrew ), Macroscelides , Galegeeska (Somali elephant shrew ), Petrosaltator (North African elephant shrew ) and Petrodromus (proboscis). The latter four form a closer unit and are summarized in the tribe of the Macroscelidini, while the former forms the Elephantulini alone. The Macroscelidinae are characterized by a palatal bone with paired openings and inhabit dry and open to scrubby landscapes. Opposite are the Rhynchocyoninae, which contain only the genus Rhynchocyon (proboscis dog). In these, in turn, the palatal bone is closed, and additional small cusps appear on the lower anterior premolars . The upper incisors are absent in today's species, but are found in extinct forms. The elephants are generally larger than the other elephants and inhabit closed habitats . In general, today's elephants tend to have high-crowned ( subhypsodontic ) molars that lack the cingulum. Furthermore, the last premolar is designed like a molar and the last molar is usually reduced.
In addition to today's subfamilies, at least four are known to have died out. The Herodotiinae form the oldest group in phylogenetic terms , the characteristics of which are the generally low-crowned ( brachyodontic ) molars, the formation of a broad cingulum at the tooth base and the presence of a rearmost molar. The subfamily is only documented from the Eocene . The Metoldobotinae currently represent a monotypical taxon. Its only species and genus is characterized by its particularly large body size and the loss of the lower rear molar. Another subfamily is occupied with the Myohyracinae , which are restricted to the Lower and Middle Miocene . Individual features suggest that the representatives of the group tended to eat herbivorous foods with a specialization in grasses and seeds . These include the first two enlarged incisors equipped with a cutting edge, which are also angled forward ( procumbent ), and also a more massive lower jaw for stronger masticatory muscles. The rearmost molars are still formed but small, but the second premolar is molarized, which increases the chewing surface of the entire row of teeth. The Mylomygalinae in turn comprise only one species and genus from the Pliocene . They are characterized by high-crowned teeth and a missing posterior molar. In addition, strongly folded enamel occurs on the chewing surfaces of the molars , as is typical of rodents . The Myohyracinae and the Mylomygalinae belong together with the Rhynchocyoninae and the Macroscelidinae according to the current view to the crown group of elephants, while the Herodotiinae and the Metoldobotinae form the trunk group.
Internal systematics of the Macroscelidea according to Hooker et al. 2012
Originally, the order of the Macroscelidea was both recent and fossil as monotypical and contained only the elephant family. Small mammals from the geological past are often only identified through the remains of their teeth. Their morphological allocation is therefore not always clear due to their often similar lifestyles and diets. Studies on postcranial skeletal material from the years 2005 and 2008 showed clear similarities between the Apheliscidae and the elephants, especially with regard to the combination of features on the hind legs and the hind feet, for example on the greatly elongated lower legs and the special characteristics of the heel and ankle bones . The latter has a deep groove for articulation with the shin joint, which is also found in elephants, snakes and aardvarks . The Apheliscidae are a North American widespread group that occurred in the late Paleocene and early Eocene in what is now the western part of the continent and had characteristic triangular to square, bunodonte (with a rounded chewing surface pattern) upper rear molars. Due to their tooth characteristics, they were initially associated with the Hyopsodontidae , which belong to the " Condylarthra ", a diverse, but not self-contained group of primitive ungulates . Closely related to the Apheliscidae are the Louisinidae , they were originally like the Apheliscidae as part of the Hyopsodontidae and represent the European counterpart of the former with a similar temporal distribution. According to the phylogenetic studies, these form the sister group of the elephants and the Apheliscidae. These results could be reproduced in further studies. However, the new analyzes also showed that if the Apheliscidae and Louisinidae are included in the Macroscelidea, as previously suggested, the Amphilemuridae and Adapisoricidae must also be taken into account. Both families (sometimes they were also synonymous) were seen as members of the insectivore for a long time and were part of the hedgehog ancestry . With regard to the Amphilemuridae, doubts arose as early as the end of the 1980s, however, both dental and skeletal anatomical features show similarities with the Apheliscidae. The varied Amphilemuridae are known from the Middle Paleocene to the Middle Eocene of North America and Europe; very well-preserved skeletal remains suggest both enlarged hind limbs and an elongated nose. The Adapisoricidae, which currently contain only one genus, are restricted to the Paleocene of Europe. The integration of the groups mentioned into the macroscelidea is not fully shared, since other authors see a convergent development in the special formation of the musculoskeletal system . In addition, depending on the study and the weighting of the individual characteristics, there are very different relationships between the individual groups. A problem for the Apheliscidae and the Louisinidae is the lack of clear skull material that could help clarify.
Overview of the families and genera of the elephant
The order of the elephants is structured as follows in the classic sense:
- Order: Macroscelidea Butler , 1956
- Family: Macroscelididae Bonaparte , 1838
- Subfamily: Herodotiinae Simons, Holroyd & Brown , 1991
- Chambius Hartenberger , 1986
- Herodotius Simons, Holroyd & Brown , 1991
- Nementchatherium Tabuce, Coiffait, Coiffait, Mahboubi & Jaeger , 2001
- Eotmantsoius Tabuce, Jaeger, Marivaux, Salem, Bilal, Benammi, Chaimanee, Coster, Marandat, Valentin & Brunet , 2012
- Subfamily: Metoldobotinae Simons, Holroyd & Brown , 1991
- Metoldobotes locksmith , 1910
- Subfamily: Macroscelidinae Bonaparte , 1838
- Palaeothentoides Stromer , 1932
- Hiwegicyon Butler , 1984
- Pronasilio Butler , 1984
- Miosengi Grossman & Holroyd , 2009
- Macroscelides A. Smith , 1829
- Galegeeska Heritage & Rayaleh , 2020
- Petrodromus Peters , 1846
- Petrosaltator Dumbacher, Carlen & Rathbun , 2016
- Elephantulus Thomas & Schwann , 1906
- Subfamily: Rhynchocyoninae Gill , 1872
- Brevirhynchocyon Senut & Georgalis , 2014
- Hypsorhynchocyon Senut , 2008
- Miorhynchocyon Butler , 1984
- Rhynchocyon Peters , 1847
- Subfamily: Myohyracinae Andrews , 1914
- Myohyrax Andrews , 1914
- Protypotheroides Stromer , 1922
- Subfamily: Mylomygalinae Patterson , 1965
- Mylomygale Broom , 1948
Although elephants had been scientifically known as living animals since the beginning of the 19th century at the latest, fossil representatives could only be clearly identified and named in the 1930s. For the first time Robert Broom succeeded in doing this on some South African representatives of Elephantulus , and later he described an extinct genus with Mylomygale . Previously named representatives were assigned to other groups. Max Schlosser referred Metoldobotes in 1910 due to similarities to Olbodotes to the extinct insectivorous Mixodectidae , which are close to the giant gliders (Schlosser also adopted the spelling mistake from Oldobotes that existed at the time ). Again four years later had Charles William Andrews Myohyrax the basis of the specialized tooth construction hyraxes asked. On the other hand, Ernst Stromer recognized Protypotheroides as a relative of the South American ungulates or the hyrax in 1921 , while ten years later he assigned palaeothentoides to the marsupials because of the supposed four existing molars (but the foremost molar was a molarized premolar). Only a detailed anatomical study from the mid-1960s provided evidence that all of these extinct forms represented elephants.
Taking into account research results since 2005, the following groups must be included in the Macroscelidea:
- Litocherus Gingerich , 1983
- Adunator Russell , 1964
- Family: Adapisoricidae Schlosser , 1887
- Adapisorex Lemoine , 1883
- Family: Amphilemuridae (= Dormaaliidae) Hill , 1953
- Neomatronella Russell, Louis & Savage , 1975
- Patriolestes Walsh , 1998
- Subfamily: Placentidentinae Russell, Louis & Savage , 1973
- Placentidens Russell, Louis & Savage , 1973
- Subfamily: Amphilemurinae Hill , 1953
- Alsaticopithecus Hürzeler , 1947
- Amphilemur Heller , 1935
- Gesneropithex Hürzeler , 1946
- Macrocranion (= Dormaalius ) Weitzel , 1949
- Pholidocercus from Koenigswald & Storch , 1983
- Subfamily: Scenopaginae Novacek , 1985
- Ankylodon Patterson & McGrew , 1937
- Scenopagus McKenna & Simpson , 1959
- Subfamily: Sespedectinae Novacek , 1985
- Colpocherus Beard & Dawson , 2009
- Crypholestes Novacek , 1980
- Proterixoides stick , 1935
- Sespedectes stick , 1935
- Zionodon Dunn & Rasmussen , 2009
- Family: Apheliscidae Matthew , 1918
- Litomylus Simpson , 1935
- Aletodon Gingerich , 1977
- Haplaletes Simpson , 1935
- Utemylus Gingerich , 1983
- Dorraletes Gingerich , 1983
- Haplomylus Matthew , 1915
- Subfamily: Apheliscinae Matthew , 1918
- Gingerichia Zack, Penkrot, Krause & Maas , 2005
- Phenacodaptes Jepsen , 1930
- Apheliscus Cope , 1975
- Family: Louisinidae Sudre & Russell , 1982
- Cingulodon De Bast & Smith , 2017
- Walbeckodon Hooker & Russell , 2012
- Paschatherium Russell , 1964
- Berrulestes Hooker & Russell , 2012
- Dipavali van Valen , 1978
- Gigarton Hooker & Russell , 2012
- Monshyus (= Prolatidens ) Sudre & Russell , 1982
- Thryptodon Hooker & Russell , 2012
- Prolouisina Hooker & Russell , 2012
- Teilhardimys (= Microhyus ) Kretzoi & Kretzoi , 2000
- Louisina Russell , 1964
Sometimes the Scenopaginae and the Sespedectinae are run as independent families.
Discovery and Taxonomy
Europeans first became aware of the elephant at the end of the 17th century. Between 1685 and 1696, Simon van der Stel (1639–1712), who later became the governor of the Cape Province , led an expedition in search of copper deposits in Namaqualand . Alongside numerous other animals, on September 25, 1685, he also sighted elephants, which the accompanying draftsman Hendrik Claudius recorded on paper. The expeditions of Robert Jacob Gordon (1743–1795), which he carried out from 1772 to 1773 and from 1777 until his death, are significant . During his fourth trip to the Cape region of southern Africa in 1779 and 1780, he observed some elephants. In his report of August 2, 1779, he named this because of the long, trunk-like, constantly moving nose as Oliphantsmuis ("elephant mouse"). He also noticed the short front and long rear legs and the high speed the animals reached. For both observations, that of 1685 and that of 1779, it is assumed that they were short-eared elephants because of their range . In 1793, Thomas Pennant used the term elephant shrew for the short-eared elephant shrew for the first time in his History of Quadrupeds , from which the German common name "elephant shrew " is derived. Pennant classified the animals within the shrews .
Seven years later, George Shaw referred to Pennant and gave the short-eared elephant the scientific name Sorex proboscideus , with which he confirmed the position within the shrews. Again almost three decades later, in 1829, Andrew Smith (1797–1872) referred the short-eared elephant to the new genus Macroscelides (but named it with the species Macroscelides typus , now a synonym for Macroscelides proboscideus ). The name is composed of the Greek words μακρὁς ( macros “large”) and σκέλος ( skélos “leg”) and thus refers to the clearly elongated rear legs. In 1838 then Charles Lucien Jules Laurent Bonaparte (1803-1857) introduced the term Macroscelidina based on the generic name. Although the name was not renamed by St. George Mivart until 1868 into the correct family name Macroscelididae, Bonaparte is considered to be the family's first descriptor. The name of the order Macroscelidea goes back to Percy M. Butler (1912-2015), who introduced it in 1956, but without defining it more precisely. That was reserved for Bryan Patterson , who in 1965 delivered a detailed study of the fossil representatives of the order compared to their recent ones.
Shrews, rodents or African animals - on the systematic position of elephants
The external similarities between the elephant and the shrew made it almost inevitable that they were included in the Insectivora ("insect eater") proclaimed by Thomas Edward Bowdich in 1821 . In addition to the shrews, these originally also included the hedgehogs , golden mole , tenreks and moles . Wilhelm Peters in 1852 and Johann Andreas Wagner in 1855, for example, managed the then known elephants among the insectivores. The increasing knowledge about the elephants, which was enriched by new discoveries in the course of the 19th century, prompted Peters to regroup the Insectivora. He established two nameless groups, one with an appendix , in which he classified the elephant next to the actual pointed squirrel and also the giant glider, and one without appendix, which contained the remaining insectivora. In the second volume of his work General Morphology of Organisms , Ernst Haeckel gave these two groups the formal names Menotyphla (with appendix) and Lipotyphla (without appendix), although he ruled out the giant gliders again.
The view that elephants were classified in the taxon Insectivora persisted well into the 20th century, even if the division into two propagated by Haeckel was partly questioned and the actual shrews should be closely related to the primates . In an anatomical study of the elephant in comparison to the actual pointed squirrel and the hedgehog, Francis Gaynor Evans recognized numerous similarities between the first two groups in 1942, for example in the large eye sockets, the fully developed zygomatic arch, the bulging occiput or the long symphysis at the pelvis formed by the ischium and pubic bone together. For him, the results of his studies meant that the division of the Insectivora into two large groups according to Haeckel actually had a real basis. George Gaylord Simpson did not follow Evans' general taxonomy of mammals. He moved the actual pointed squirrels to the primates and subdivided the then order Insectivora into five recent superfamilies, one of which represented the elephant under the name Macroscelidoidea; Theodore Nicholas Gill introduced the term in 1872. It was later correctly noted that the skeletal features used by Evans are to be understood as rather primitive properties of the higher mammals ( plesiomorphism ) and therefore do not represent the common acquired characters ( synapomorphism ) of the elephants and the actual pointed squirrels.
During the investigation of the fossilized skulls of insectivores and their extinct relatives, Percy M. Butler was able to work out important differences to the elephant-shrews and the actual shrews in 1956. This concerns, for example, the construction of the eye window and the skull bones involved, as well as the arrangement of the masticatory muscles, which prompted Butler to dissolve the menotyphla and to place the shrews near the primates. He referred the elephants to their own order Macroscelidea with a closer position to the shrews and primates than to the insectivores. A relatively close relationship between the elephant and the insectivore remained for the time being, for example with Leigh Van Valen 1967, who saw the Macroscelidea as a subordination within the Insectivora. In the mid-1970s, however, Malcolm C. McKenna postulated a close relationship with the rabbit-like . To do this, McKenna united the two groups under the taxon Anagalida. He derived the Macroscelidea from the original representatives of the Anagalidae , which lived in Asia in the Paleocene and did not yet have the fused bones of the elephant's lower leg or an unreduced third molar. Michael J. Novacek largely agreed with this in 1986 after he had presented a detailed study of the skulls of primeval, insectivore-like animals. In its systematics, the elephants stood opposite the glires , which summarize the rodents and the hare-like, as a sister group . McKenna repeated his view with Susan K. Bell in 1997 in their Classification of Mammals.
Only biochemical and molecular genetic studies that emerged in the late 20th century brought a new perspective . Analysis of structural proteins already revealed the mid-1980s a possible closer relationship of elephant shrews to elephants and hyraxes . This was then confirmed by genetic studies at the end of the 1990s, which additionally revealed a closer relationship between the elephants and the tenreks, golden mole rats and the aardvark and thus to insectivorous animals native to Africa. This is why this externally highly variable group was given the name Afrotheria . These results could be supported by later investigations, among other things by the isolation of a specific retroposon , the so-called Afro SINE , which all representatives of Afrotheria have in common.
The origin of the elephant
The Macroscelidea represent an ancient group of higher mammals , which has been detectable in Africa at least since the Lower or Middle Eocene . The origin of the group has not yet been clarified. Assuming a close relationship with the Glires and the extinct Anagalidae, an origin from Asia would be assumed. This relationship, however, contradicts individual anatomical findings, especially on the tarsus. Accordingly, the morphological similarities between rodents and elephants, which can be observed in the structure of the limbs, represent a rather parallel development in similar modes of locomotion. Some researchers, on the other hand, prefer a derivation of elephants from the highly diverse group of " Condylarthra " ( Apheliscidae and Louisinidae ) with the inclusion of other groups ( Amphilemuridae and Adapisoricidae ), which for various reasons were placed in the vicinity of the insectivores. In accordance with ancestry from the Anagalidae, this would shift the origin of the Macroscelidea far back into the Paleocene , but the four groups mentioned were common in today's North America and Europe at that time. Both the Apheliscidae in North America and the Louisinidae in Europe first appeared 63 to 62 million years ago. The other representatives are mostly proven from the Eocene. Among other things, very well-preserved skeletons from the Messel Pit of Macrocranion and Pholidocercus from the group of Amphilemuridae have come down to us, dating back to the Middle Eocene around 47 million years ago. Already at that time there was evidence of an exchange of fauna with Africa, as individual members of the Louisinidae also occur in northern Africa.
The earliest occurrence of the Macroscelididae family falls in the Lower and Middle Eocene. It first appeared in northern Africa with the Herodotiinae subfamily . The Chambi site in Tunisia , after which Chambius was named, is significant in this context . This most primitive member of the family to date has been found in numerous skull remains and teeth as well as parts of the body skeleton, which suggest a small animal weighing an estimated only 13 g. While the tooth structure is still very original, adaptations to a cursorial way of life can already be recognized in the musculoskeletal system . This is supported by the ridges on the roll-like trochlea of the ankle , which stabilized the foot laterally during dynamic movements, but also the elongated formation of the calcaneus , which is characteristic of fast-moving animals. In contrast to today's species, Chambius did not yet have an inflated tympanic bladder or enlarged ear ossicles, so that the animals may not yet be able to perceive sounds in low frequencies. The genus is possibly also occupied by a single molar tooth from the Glib-Zegdou formation in the Gour Lazib region in Algeria . This dates back to the transition to the Middle Eocene. Around this time Eotmantsoius and Nementchatherium also appear in Dor el-Talha in Libya . However, the first type is only based on a single tooth. In addition to a fragmented left upper jaw, numerous isolated teeth were discovered from the latter. Nementchatherium is also documented about single teeth from the late Middle Eocene site of Bir El Ater in Algeria. Compared to the older Chambius, the shape shows a clearly molarized last premolar. The lower sections of the Gebel Quatrani Formation of the Fayyum in Egypt became Herodotius . described. The shape is named after the Greek historian and geographer Herodotus , who lived in the 5th century BC. Described the ancient cities of Fayyum. The genus is based on several upper and lower jaw fragments, the age of which is estimated to be around 34 million years, which means they belong to the Upper Eocene. Some sites in the diamond restricted area of Namibia in southwestern Africa also contain fossils of elephants that have not yet been scientifically described. They date to the Middle to Upper Eocene.
From the subsequent Oligocene there are only few records of the Macroscelididae. In the upper areas of the Gebel-Quatrani formation, Metoldobotes from the subfamily of Metoldobotinae have so far occurred. The genus is represented by at least one lower jaw and one tooth. The length of the complete row of teeth is 32 mm, which makes Metoldobotes significantly larger than its predecessor. The Upper Oligocene Nsungwe Formation of the Rukwa Basin in southwestern Tanzania contained the remains of elephants in two forms, a smaller and a larger one. They stand as an intermediary between the older representatives of the Paleogene and the younger representatives of the Neogene , but the material has not yet been formally evaluated.
In the Lower Miocene , the Macroscelididae are present for the first time in eastern and southern Africa, their main area of distribution today. The Myohyracinae are a specialty , whose special structure of the molars suggests a stronger plant-based diet. One of the most common forms is Myohyrax , which was first described by Karungu in Kenya using a fragment of the lower jaw. To date, around 50 other remains of the lower jaw have been found from the site, and more than two dozen fossil remains were found in the Hiwegi Formation of Rusinga , an island in Lake Victoria , and in the adjacent Kaswanga. The well-known find material also includes some postcranial skeletal parts, which are reminiscent of the Macroscelidinae, especially the proboscis, in their design. Most of the fossil material dates back to around 20 to 17 million years. The most recent finds in East Africa come from Fort Ternan , also in southwestern Kenya, and are around 13.8 million years old. In Namibia , Myohyrax, with more than 400 individual finds from Arrisdrift on the Oranje alone, is the most common Miocene representative of the elephant. The material consists mainly of dentition and teeth and belongs to the same period as most of the East African finds. A few more mandibular fragments from the region around Lüderitz in southwestern Namibia are related to the closely related Protypotheroides , which reached the size of today's proboscis dog.
Also in the Lower Miocene, representatives can be found for the first time that are in the line of development of today's species. Miorhynchocyon represents the Rhynchocyoninae and thus the proboscis dog, it lived in East Africa from 22 to 14 million years ago and includes several species. In terms of size, the animals did not yet come close to today's shapes. At about the same time, brevirhynchocyon and hypsorhynchocyon appeared in southern Africa , numerous skeletal elements of which have been uncovered in the Orange region . The Macroscelidinae are also documented very early and form a diverse group with just four extinct genera. However, the found material is rather limited, so that there are still some uncertainties. Hiwegicyon was described on the basis of a lower jaw of a non-adult animal from the Hiwegi formation of Kaswanga. The Lothidok Formation in northwestern Kenya contained a lower jaw fragment with only one remaining molar and the tooth socket of another, which is assigned to Miosengi . The second molar still shows some very primitive features, such as the low crown height. Both sites are ascribed an age of 17.8 to 16.8 million years. Again from Fort Ternan there are three remains of Pronasilio's teeth . Here, too, individual primeval features such as the formation of the rearmost third molar and the slightly molarized fourth premolar can still be seen.
From the further course of the Middle and Upper Miocene, no remains of elephants are known. Only from Egypt have individual teeth and a long bone from the karst area in the Libyan desert in the west of the country been described, which may belong to Rhynchocyon . The finds are between 10 and 11 million years old, at that time the area of today's Sahara was much more humid.
Plio and Pleistocene
It was not until the Pliocene that elephants reappear more frequently, as a rule they belong to the modern lines of development. In East Africa, Rhynchocyon with some upper and lower jaws has been found in Laetoli in Tanzania . The age of the site is between 3.5 and 3.6 million years. Finds from South African caves can also be classified around the same period. Makapansgat is of outstanding position , in whose breccias around 250 individuals of elephants have so far been discovered. Most of the finds are assigned to Elephantulus , a few represent Macroscelides . Both genera have their oldest fossil record here. Already in the transition to the Pleistocene around 2.5 million years ago are the important sites of Sterkfontein and Swartkrans , in which elephants also occur to a considerable extent.
Palaeothentoides possibly also belongs to the transition from the Pliocene to the Pleistocene , of which only a few remains of the lower jaw from river deposits from Klein Zee south of Port Nolloth in western South Africa have come down to us. In this representative of the Macroscelidinae, as in most of the fossil genera of the group, the last molar is still formed. The only form of that time that does not belong in the modern line of development is Mylomygale from the subfamily of the Mylomygalinae. It was set up on the basis of a lower jaw that was found in a cave just a few hundred meters north of the famous Taung site , its exact age is unknown. In the further course of the Pleistocene, especially Elephantulus and Macroscelides are documented in southern and much less often in eastern Africa. Only from Petrodromus there is still no fossil record.
In German-speaking countries, the term “elephant shrew”, which was sometimes used for the entire family, was partly replaced by “elephant shrew”. On the one hand it refers to the trunk-like nose, on the other hand to the typical jumping locomotion. In the English- speaking world, on the other hand, the Swahili word Sengi , which has the same meaning and was first used in 1997 by Jonathan Kingdon , prevailed over the traditional name elephant-shrew ("elephant shrew ") . Sengi is derived from Kigiriama , a Bantu language where it is sanje . Reasons for turning away from "elephant shrew " or elephant-shrew are on the one hand the knowledge that the elephant shrews are not related to the shrews , on the other hand their endemic distribution in Africa, which advocates an independent name.
The species that inhabit dry to desert-like landscapes, i.e. all representatives of the genus Macroscelides and a larger part of the elephant shrews, are not endangered. Since these areas are rather unattractive for the people, there is little potential for conflict and the expansion of human settlements or economic areas is very limited or limited to river valleys. In contrast, the populations of the inhabitants of forest landscapes, i.e. all representatives of the elephant dog, show strong declines. The main causes are the deforestation and destruction of forests and the resulting islanding of the animal habitat. In addition, three of the four known species of the elephant dog have a very limited range. Because of this, they are classified as threatened by the IUCN . The proboscis is widespread and is generally not considered to be endangered, but locally, individual populations are at great risk. For some species, due to their rarity, no information on the threat to the population can be given.
- Stephen Heritage: Macroscelididae (Sengis). In: Don E. Wilson and Russell A. Mittermeier (eds.): Handbook of the Mammals of the World. Volume 8: Insectivores, Sloths and Colugos. Lynx Edicions, Barcelona 2018, pp. 206-234 ISBN 978-84-16728-08-4
- Patricia A. Holroyd: Macroscelidea. In: Lars Werdelin and William Joseph Sanders (eds.): Cenozoic Mammals of Africa. University of California Press, Berkeley / London / New York 2010, pp. 89-98
- Jonathan Kingdon, David Happold, Michael Hoffmann, Thomas Butynski, Meredith Happold, Jan Kalina (Eds.): Mammals of Africa Volume I. Introductory Chapters and Afrotheria. Bloomsbury, London 2013, pp. 258-287
- Gea Olbricht, Alexander Sliwa: Elephant shrews - the elephants' little relatives? Journal of the Cologne Zoo 53 (3), 2010, pp. 135–147
- Galen B. Rathbun: Why is there discordant diversity in sengi (Mammalia: Afrotheria: Macroscelidea) taxonomy and ecology? African Journal of Ecology 47, 2009, pp. 1-13
- ↑ John P. Dumbacher, Galen B. Rathbun, Timothy O. Osborne, Michael Griffin and Seth J. Eiseb: A new species of round-eared sengi (genus Macroscelides) from Namibia. Journal of Mammalogy 95 (3), 2014, pp. 443-454
- ↑ Francesco Rovero, Galen B. Rathbun, A. Perkin, T. Jones, DO Ribble, C. Leonard, RR Mwakisoma and N. Doggart: A new species of giant sengi or elephant-shrew (genus Rhynchocyon ) highlights the exceptional biodiversity of the Udzungwa Mountains of Tanzania. Journal of Zoology 274 (2), 2008, pp. 126-133
- ↑ Michael F. Schneider and Victorino a Buramuge: Atlas of the microscopic hair structure of Southern African shrews, hedgehogs, goldem moles and elephant-shrews (Mammalia). Bonn zoological contributions 54 (3), 2006, pp. 103–172
- ↑ a b c d e f g h i j k l m Jonathan Kingdon, David Happold, Michael Hoffmann, Thomas Butynski, Meredith Happold and Jan Kalina (eds.): Mammals of Africa Volume I. Introductory Chapters and Afrotheria. Bloomsbury, London, 2013, pp. 258-287
- ↑ a b c d e f g h i j k l m n o Stephen Heritage: Macroscelididae (Sengis). In: Don E. Wilson and Russell A. Mittermeier (eds.): Handbook of the Mammals of the World. Volume 8: Insectivores, Sloths and Colugos. Lynx Edicions, Barcelona 2018, pp. 206-234 ISBN 978-84-16728-08-4
- ^ A b Gea Olbricht and William T. Stanley: The topographic distribution of the penis and mammary glands in sengis (Macroscelidea) and its usefulness for taxonomic distinctions. Zoosystematics and Evolution 85 (2), 2009, 297-303
- ↑ Jan Ihlau, Friederike Kachel and Ulrich Zeller: Graphical description of the ventral side of a sengi's (Macroscelides proboscideus) skull. Afrotherian Conservation 4, 2006, pp. 11-12
- ^ Matthew J. Mason: Structure and function of the mammalian middle ear. I: Large middle ears in small desert mammals. Journal of Anatomy 228 (2), 2016, pp. 284-299, doi: 10.1111 / joa.12313
- ^ A b c d Francis Gaynor Evans: The osteology and relationships of the elephant-shrews (Macroscelididae). Bulletin of the American Museum of Natural History 80, 1942, pp. 85-125
- ↑ a b c d e f g h B. Patterson: The fossil elephant shrews (Family Macroscelididae). Bulletin of The Museum of Comparative Zoology 133, 1965, pp. 297-335
- ^ A b Wilhelm Peters: Scientific trip to Mossambique: carried out on the orders of His Majesty the King Friedrich Wilhelm IV in the years 1842 to 1848. Berlin, 1852, pp. 1–205 (pp. 87–110) (  )
- ^ William Kitchen Parker: On the Structure and Development of the Skull in the Mammalia. Part III. Insectivora. Transactions of the Philosophical Society of London 176, 1885, pp. 121–275 (pp. 241–249)
- ↑ Jean E. Kratzing and Peter F. Woodall: The rostral nasal anatomy of two elephant shrews. Journal of Anatomy 157, 1988, pp. 135-143
- ↑ Peter F. Woodall and RI Mackie: Caecal size and function in the rock elephant shrew Elephantulus myurus (Insectivora, Macroscelididae) and the Namaqua rock mouse Aethomys namaquensis (Rodentia, Muridae). Comparative Biochemistry and Physiology 87A, 1987, pp. 311-314
- ↑ Peter F. Woodall: Digestive tract dimensions and body mass of elephant shrews (Macroscelididae) and the effects of season and habitat. Mammalia 51 (4), 1987, pp. 537-545
- ↑ a b CT Downs: Renal structure, and the effect of an insectivorous diet on urine composition of Southern African Elephant-Shrew species (Macroscelidea). Mammalia 60 (4), 1996, pp. 577-589
- ↑ Cornelius Jan van der Horst: Some observations of the structure of the genital tract of Elephantulus. Journal of Morphology 70, 1942, pp. 403-429
- ↑ a b HRH Tripp: Reproduction in elephant-shrews (Macroscelididae) with special reference to ovulation and implantation. Journal of Reproduction and Fertility 26, 1971, pp. 149-159
- ^ PF Woodall: The penis of elephant shrews (Masmmalia: Macroscelididae). Journal of Zoology 237, 1995, pp. 399-410
- ↑ Jason A. Kaufman, Gregory H. Turner, Patricia A. Holroyd, Francesco Rovero and Ari Grossman: Brain Volume of the Newly-Discovered Species Rhynchocyon udzungwensis (Mammalia: Afrotheria: Macroscelidea): Implications for Encephalization in Sengis. PlosOne 8 (3), 2013, p. E58667, doi: 10.1371 / journal.pone.0058667
- ↑ a b c d e f g h i j Galen B. Rathbun: Why is there discordant diversity in sengi (Mammalia: Afrotheria: Macroscelidea) taxonomy and ecology? African Journal of Ecology 47, 2009, pp. 1-13
- ^ A b Barry G. Lovegrove and Metobor O. Mowoe: The evolution of micro-cursoriality in mammals. The Journal of Experimental Biology 217, 2014, pp. 1316-1325
- ↑ Juri A. Miyamae, Talia Y. Moore and Galen B. Rathbun: Observations on an Unusual “Arrhythmic” Gait in Sengis. Afrotherian Conservation 14, 2018, pp. 44–47
- ^ J. Clevedon Brown: Observations on the Elephant shrews (Macroscelididae) of equatorial Africa. Proceedings of the Zoological Society of London 143, 1964, pp. 103-119
- ↑ a b c d e Galen B. Rathbun: Order Macroscelidea. In: John D. Skinner and Christian T. Chimimba (Eds.): The Mammals of the Southern African Subregion. Cambridge University Press, 2005, pp. 22-34
- ↑ AS Faurie, ER and MR Dempster Perrin: Footdrumming patterns of southern African elephant-shrews. Mammalia 60 (4), 1996, pp. 567-576.
- ^ Fred W. Koontz and Nancy J. Roeper: Elephantulus rufescens. Mammalian Species 204, 1983, pp. 1-5
- ^ Sasha Hoffmann, Nigel C. Bennett, Bettine Jansen van Vuuren and Heike Lutermann: Space use and the evolution of social monogamy in eastern rock sengis. Ethology 126 (4), 2020, pp. 393-402, doi: 10.1111 / eth.12983
- ^ A b Clare D. FitzGibbon: The adaptive significance of monogamy in the golden-rumped elephant-shrew. Journal of Zoology 242, 1997, pp. 167-177
- ↑ Melanie Schubert, Neville Pillay, David O. Ribble and Carsten Schradin: The Round-Eared Sengi and the Evolution of Social Monogamy: Factors that Constrain Males to Live with a Single Female. Ethology 115, 2009, pp. 972-985
- ↑ Melanie Schubert, Carsten Schradin, Heiko G. Rödel, Neville Pillay and David O. Ribble: Male mate guarding in a socially monogamous mammal, the round-eared sengi: on costs and trade-offs. Behavioral Ecology and Sociobiology 64, 2009, pp. 257-264
- ^ David O. Ribble and Michael R. Perrin: Social organization of the Eastern Rock Elephant-shrew (Elephantulus myurus): the evidence for mate guarding. In: Belgian Journal of Zoology 135 (suppl.), 2005, pp. 167-173.
- ↑ Petra Wester: Sticky snack for sengis: The Cape rock elephant-shrew, Elephantulus edwardii (Macroscelidea), as a pollinator of the Pagoda lily, Whiteheadia bifolia (Hyacinthaceae). Natural Sciences 97, 2010, pp. 1107–1112
- ↑ Steven D. Johnson, Priscilla M. Burgoyne, Lawrence D. Harder and Stefan Dötterl: Mammal pollinators lured by the scent of a parasitic plant. Proceedings of the Royal Society B 278, 2011, pp 2303-2310
- ^ Mike Perrin: Comparative aspects of the metabolism and thermal biology of elephant-shrews (Macroscelidea). Mammal Review 25, 1995, pp. 61-78
- ↑ Colleen T. Downs and Mike R. Perrin: The thermal biology of three Southern African Elephant-shrews. Journal of Thermal Biology 20 (6), pp. 445-450
- ^ Susan Lumpkin and Fred W. Koontz: Social and Sexual Behavior of the Rufous Elephant-Shrew (Elephantulus rufescens) in Captivity. Journal of Mammalogy 67 (1), 1986, pp. 112-119
- ^ Galen B. Rathbun and CD Rathbun: Social structure of the bushveld sengi (Elephantulus intufi) in Namibia and the evolution of monogamy in the Macroscelidea. Journal of Zoology 269, 2006, pp. 391-399
- ^ Galen B. Rathbun: The social structure and ecology of Elephant-shrews. Zeitschrift für Tierpsychologie Beiheft 20 (Advances in Behavioral Research), 1979, pp. 1-76
- ↑ EG Sauer: On the social behavior of the short-eared elephant shrew Macroscelides proboscideus. Zeitschrift für Mammaliankunde 38, 1973, pp. 65-97
- ^ Gea Olbricht: Longevity and fecundity in sengis (Mavcroscelidea). Afrotherian Conservation 5, 2007, pp. 3-5
- ^ A b Matjaž Kuntner, Laura J. May-Collado and Ingi Agnarsson: Phylogeny and conservation priorities of afrotherian mammals (Afrotheria, Mammalia). Zoologica Scripta 40 (1), 2011, pp. 1-15
- ↑ Erik R Seiffert: A new estimate of afrotherian phylogeny based on simultaneous analysis of genomic, morphological, and fossil evidence. BMC Evolutionary Biology 7, 2007, p. 224, doi: 10.1186 / 1471-2148-7-224
- ↑ a b Robert W. Meredith, Jan E. Janečka, John Gatesy, Oliver A. Ryder, Colleen A. Fisher, Emma C. Teeling, Alisha Goodbla, Eduardo Eizirik, Taiz LL Simão, Tanja Stadler, Daniel L. Rabosky, Rodney L. Honeycutt, John J. Flynn, Colleen M. Ingram, Cynthia Steiner, Tiffani L. Williams, Terence J. Robinson, Angela Burk-Herrick, Michael Westerman, Nadia A. Ayoub, Mark S. Springer and William J. Murphy: Impacts of the Cretaceous Terrestrial Revolution and KPg Extinction on Mammal Diversification. Science 334, 2011, pp. 521-524
- ^ A b Peter J. Waddell, Hirohisa Kishino, and Rissa Ota: A Phylogenetic Foundation for Comparative Mammalian Genomics. Genome Informatics 12, 2001, pp. 141-154
- ↑ a b c d Rodolphe Tabuce: New remains of Chambius kasserinensis from the Eocene of Tunisia and evaluation of proposed affinities for Macroscelidea (Mammalia, Afrotheria). Historical Biology 30 (1-2), 2018, pp. 251-266, doi: 10.1080 / 08912963.2017.1297433
- ↑ a b c d e f g h i Patricia A. Holroyd: Macroscelidea. In: Lars Werdelin and William Joseph Sanders (eds.): Cenozoic Mammals of Africa. University of California Press, Berkeley, London, New York, 2010, pp. 89-98
- ↑ Galen B. Rathbun: Sengi Taxonomy - a 2017 update. Afrotherian Conservation 13, 2017, pp. 9-10
- ↑ a b Steven Heritage, Houssein Rayaleh, Djama G. Awaleh and Galen B. Rathbun: New records of a lost species and a geographic range expansion for sengis in the Horn of Africa. PeerJ 8, 2020, p. E9652, doi: 10.7717 / peerj.9652
- ^ A b Percy M. Butler: Fossil Macroscelidea. Mammal Review 25 (1/2), 1995, pp. 3-14
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- ↑ Shawn P. Zack, Tonya A. Penkrot, David W. Krause and Mary C. Maas: A new apheliscine 'condylarth' mammal from the late Paleocene of Montana and Alberta and the phylogeny of 'hyopsodontids'. Acta Palaeontologica Polonica 50 (4), 2005, SD. 809-830
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- ^ IUCN: The IUCN Red List of Threatened Species. Version 2015.2. (  ); last accessed on August 16, 2015
- Photos and videos about the elephants (Sengi) of the California Academy of Sciences , created by Galen B. Rathbun ( Afrotheria Specialist Group of the IUCN)